This invention relates to a method and device for improving cardiac function, particularly where there is congestive heart failure.
Congestive heart failure occurs, inter alia, where there has been a heart attack or an infection. In either case, the pumping action of the heart is impaired. In another malfunction, left ventricular hypertrophy, the myocardium of the left ventricle becomes thickened to the point of interfering with effective heart contraction.
A surgical procedure for treating congestive heart failure, developed by a doctor in Brazil, involves removing a triangular portion of a patient""s heart. In this operation, approximately one-third of the patient""s left ventricular muscle is removed. The result is that the smaller heart pumps more efficiently.
This new technique of course requires open heart surgery, with its attendant expense and extended convalescence.
An object of the present invention is to provide a surgical method for treating congestive heart failure.
A further object of the present invention is to provide such a surgical method which is less expensive than the above-described surgical technique.
It is another object of the present invention to provide a surgical method for treating congestive heart failure which may be implemented through minimally invasive procedures.
An additional object of the present invention is to provide a device for implementing such a surgical method.
These and other objects of the present invention will be apparent from the drawings and descriptions herein.
The present invention is directed to the disposition of a cardiac insert or implant in a patient""s heart so as to reduce ventricular volume, thereby improving cardiac function.
More specifically, pursuant to one embodiment of the present invention, a method for improving cardiac function comprises inserting a compressive device into a patient in a region including the patient""s heart, and thereafter operating the compressive device to bring opposite walls of a ventricle of the patient""s heart into at least approximate contact with one another to thereby constrict and close off a lower portion of that ventricle. Pursuant to a feature of the present invention, the compressive device is operated to effectively close off only the lower portion of only the one ventricle. Preferably, the one ventricle is the left ventricle of the patient""s heart. The left ventricle remains a single cell chamber of smaller volume.
In a more particular implementation of the present invention, the compressive device is inserted through a trocar sleeve or cannula which extends through a chest wall of the patient. In another particular implementation, the compressive device includes a tensile member which is inserted or introduced into the patient through a catheter with a leading end portion guided to a region of the patient""s heart. More particularly, a leading end portion of the catheter is inserted into the patient""s heart, the tensile member being ejected from the leading end portion of the catheter into cardiac tissues. Where the leading end portion of the catheter is inserted into the right ventricle, the tensile member is ejected through the septum of the patient""s heart and the left ventricle and into a myocardial wall of the heart. Where the leading end portion of the catheter is inserted into the left ventricle, the tensile member includes a first segment ejected into or through the septum of the patient""s heart and a second segment ejected through or into the myocardial wall of the left ventricle. In either case, operating of the compressive device includes exerting a tension force on the tensile member to draw the septum and the myocardial wall together. In the latter case, the two segments of the tensile member are twisted about one another to draw the septum and the myocardial wall towards one another.
Where the compressive device is a tensile member such as a wire or a suture (made of metal or polymeric material), it may be formed with one or more barbs, particularly at an end, for anchoring the tensile member in the cardiac tissues.
Where the compressive device is inserted through a trocar sleeve or cannula, the compressive device may also take the form of a tensile member such as a wire guided to a predetermined location on the myocardium of the left ventricle by a catheter inserted into a pericardial space about the patient""s heart through the trocar sleeve or cannula. The operating of the compressive device includes ejecting the tensile member from the leading end portion of the catheter through a myocardial wall, a left ventricle of the patient""s heart and a septum of the heart. The operating of the compressive device further includes exerting a tension force on the tensile member to draw the septum and the myocardial wall of the left ventricle together.
The compressive device, a tensile member in particular embodiments of the present invention, serves to reduce the volume of the left ventricle and only the left ventricle of the patient""s heart. The application of the compressive device thus serves to correct certain conditions of the patient""s heart in which the pumping capacity of the left ventricle has been reduced. The reduction in the volume of the left ventricle results in a higher blood pressure and thus a more effective transmission of blood especially to peripheral tissues of the patient.
The method of the invention contemplates an anchoring of one end of the tensile compressive member to a septum of the patient""s heart and an opposite end of the tensile compressive member to a myocardial sidewall of the left ventricle. The anchoring of the tensile compressive member may be implemented by placing a flanged or barbed element of the tensile member in contact with heart tissues. The barbed element may be embedded inside myocardial tissues or caught in an external surface of the myocardium or septum.
In some embodiments of the present invention, the compressive member may take the form of an elongate tack ejected from a tubular member such a catheter or trocar sleeve or cannula.
It is apparent, therefore, that the present invention is directed in part to a method for reducing ventricular volume, wherein a catheter is inserted into a ventricle of a patient""s heart, a cardiac insert or implant is deployed from a leading end portion of the catheter, and the cardiac insert or implant is disposed in the patient""s heart to reduce the volume of only a left ventricle of the patient""s heart. It is contemplated that the cardiac insert or implant takes the form of a tensile member such as a wire which is attached to the patient""s heart. However, other forms of inserts or implants may be effective to reduce ventricular volume.
A surgical method in accordance with the present invention treats congestive heart failure. The method may be performed thoracoscopically which is less expensive and less traumatic to the patient than an open-heart surgical technique. The minimally invasive, intravascularly implemented procedure is even less expensive and less traumatic to the patient. The method of the invention is simple and reliable.